[libvirt-users] Centos 7.1.1503 + libvirt 1.2.14 = broken direct network mode

[Laine Stump]

On 04/08/2015 09:38 AM, mxs kolo wrote:
> Hi all.
>
> I use LXC on Centos 7 x86-64, with libvirt version 1.2.6 and 1.2.12
> My container has bridged network:
> # virsh dumpxml test1
> <domain type='lxc'>
>   <name>test1</name>
>   <uuid>518539ab-7491-45ab-bb1d-3d7f11bfb0b1</uuid>
>   <memory unit='KiB'>1048576</memory>
>   <currentMemory unit='KiB'>1048576</currentMemory>
>   <memtune>
>     <hard_limit unit='KiB'>1048576</hard_limit>
>     <soft_limit unit='KiB'>1048576</soft_limit>
>     <swap_hard_limit unit='KiB'>2097152</swap_hard_limit>
>   </memtune>
>   <vcpu placement='static'>2</vcpu>
>   <os>
>     <type arch='x86_64'>exe</type>
>     <init>/sbin/init</init>
>   </os>
>   <clock offset='utc'/>
>   <on_poweroff>destroy</on_poweroff>
>   <on_reboot>restart</on_reboot>
>   <on_crash>restart</on_crash>
>   <devices>
>     <emulator>/usr/libexec/libvirt_lxc</emulator>
>     <filesystem type='block' accessmode='passthrough'>
>       <source dev='/dev/data/test1'/>
>       <target dir='/'/>
>     </filesystem>
>     <filesystem type='ram' accessmode='passthrough'>
>       <source usage='524288' units='KiB'/>
>       <target dir='/dev/shm'/>
>     </filesystem>
>     <interface type='direct'>
>       <mac address='02:00:00:1a:a9:54'/>
>       <source dev='br0' mode='bridge'/>
>     </interface>

Why are you using macvtap ("type='direct') to connect to a bridge
device? You should either use macvtap to connect directly to a physical
ethernet (e.g. eth0) *or* you should use a standard tap device
("type='bridge'") to connect to the bridge. Although it might work to
connect to a bridge using macvtap, I can't think of any reason you would
want to do it that way (and that may be the source of the error you're
seeing - since macvtap isn't intended to be used that way, that scenario
probably doesn't get much, if any, testing).